feat_sdk 0.1.0

Dart and Flutter client for the feat feature-flag platform: sync flag getters, change listeners, live SSE streaming, anonymous contexts, and offline snapshots.

example/lib/main.dart

// A minimal Flutter app demonstrating feat_sdk: initialize, read a boolean
// flag, listen for changes, and swap the context. It wires up the optional
// Flutter glue (shared_preferences storage + lifecycle observer) from
// feat_flutter.dart.

import 'dart:async';

import 'package:feat_sdk/feat_sdk.dart';
import 'package:flutter/material.dart';

import 'feat_flutter.dart';

Future<void> main() async {
  WidgetsFlutterBinding.ensureInitialized();

  final storage = await SharedPreferencesFeatStorage.create();

  final client = await FeatClient.initialize(FeatClientConfig(
    // Use a client-side id key (prefix feat_cs_) or a mobile key. Both are
    // non-secret client keys and safe to ship in an app.
    apiKey: 'feat_cs_your_key_here',
    anonymous: true, // mint a stable per-install anonymous context
    storage: storage, // persist the anonymous key + offline snapshots
    // Streaming follows the change subscription by default; polling is the
    // safety net.
  ));

  runApp(ExampleApp(client: client));
}

class ExampleApp extends StatefulWidget {
  final FeatClient client;

  const ExampleApp({super.key, required this.client});

  @override
  State<ExampleApp> createState() => _ExampleAppState();
}

class _ExampleAppState extends State<ExampleApp> {
  late final FeatLifecycleObserver _observer;
  StreamSubscription<FlagChange>? _changes;

  @override
  void initState() {
    super.initState();

    // Pause/resume live updates with the app lifecycle.
    _observer = FeatLifecycleObserver(widget.client)..attach();

    // Re-render whenever a flag value flips. Subscribing also opens the live
    // stream under the default streaming policy.
    _changes = widget.client.changes.listen((change) {
      if (mounted) setState(() {});
    });
  }

  @override
  void dispose() {
    _observer.detach();
    _changes?.cancel();
    unawaited(widget.client.close());
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    final enabled = widget.client.getBool('checkout-v2', false);
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(title: const Text('feat_sdk example')),
        body: Center(
          child: Column(
            mainAxisAlignment: MainAxisAlignment.center,
            children: [
              Text('checkout-v2 is ${enabled ? 'ON' : 'OFF'}'),
              const SizedBox(height: 16),
              ElevatedButton(
                onPressed: () => widget.client.setContext(
                  EvalContext.user('user-123', attributes: {'plan': 'pro'}),
                ),
                child: const Text('Identify as user-123 (pro)'),
              ),
            ],
          ),
        ),
      ),
    );
  }
}